The present invention relates to a disk device and, in particular, a disk device which is equipped with a plurality of disk drives.
A high performance computer system generally has a host system such as CPU and a secondary storage device such as a magnetic disk. The host system reads necessary data out of the secondary storage device whenever need arises and writes the data thereinto. In addition to the magnetic disk, the secondary storage device includes a disk device having a nonvolatile storage medium, which is randomly accessible, such as an optical disk.
There has recently been a trend that the storage capacity of a disk device is increasing, which is equipped with a large number of small disk drives (hereinafter simply referred to as “drives”), and the demand for further upgrading, miniaturization as well as an increase in the storage capacity, is developing into a pressing necessity. Namely, a demand for high packaging density is increasing. In response to this demand, a disk device has been adopted which has plural drives three-dimensionally arranged in a chassis. More specifically speaking, columns of drives, in which drives are arranged in a depth (Y) direction in a chassis, are arranged in height (Z) and width (X) directions.
However, when failure occurs in a drive installed in this disk device, it will be necessary to carry out replacement of a failed drive with a normal drive. In order to make preparations for such an occasion, the disk device generally has a space between neighboring columns of drives. This will create limitation on seeking for better packaging density of drives. Disk devices for which replacement of drives can be carried out outside a chassis have been proposed recently. For example, Japanese Published Patent Application 08-137631, paragraphs 0011 to 0022 and FIG. 1, and Japanese Published Patent Application 07-6004, paragraphs 0019 to 0033 and FIG. 4, disclose related arts.
In a disk device disclosed in JP08-137631, plural slots, each of which has two drives in depth (Y) and height (Z) directions, respectively, are arranged in a height (Z) direction. These slots are adapted to be drawn out from a chassis of the disk device. When failure occurs in a drive installed in the disk device, typical repair is done in the following manner by an operator: drawing out a slot including the failed drive, replacing the failed drive with a normal one outside a chassis and restoring the slot to an original position in the chassis. It is assumed that other normal disks of this disk device may continue to work while the slot is drawn out from the chassis.
On the other hand, a disk device disclosed in JP07-6004, two columns of drives, each of which has five or six drives in a depth (Y) direction, are arranged in a width (X) direction. Furthermore, the disk device has plural panels in its height (Z) direction, which have an electronic card (adapter device). These plates are adapted to be drawn out from a chassis of the disk device. In the case of failure of a drive installed in the disk device, it is possible to conduct replacement of drives outside the chassis.
However, the disk device disclosed in JP 08-137631 has a drawback that when the slot is drawn out, efficiency of cooling provided by a fan decreases due to an undesirably long distance between drives and the fan. Furthermore, ambient air flows into the slot through an opening of the chassis for drawing out the slot, thereby disturbing the flow of cooling air. This means that this disk device is not able to provide sufficient cooling for drives while the slot is drawn out. As this disk device has no provision for packaging plural drives in a width (X) direction, it is difficult to increase its capacity of storage.
The disk device disclosed in JP07-6004, in which not only two columns of drives are spaced by the width of a board of electronic card (adapter device), but also its board surface and a surface of rotation for a drive are positioned parallel to each other, inevitably has a low packaging density in a width (X) direction.